In addition, genes in both the proliferative (including KI-67, CCNB1, and MYBL2) and invasive (MMP11 and CTSL2) groups of the 21-gene group were significantly less expressed in IDC-DCIS tumors than in IDC alone (Zeng et al. 2021). This evidence concerns the gene CTSV and ductal breast carcinoma in situ.